AuthorTopic: HRM accuracy (Read 18972 times)

canadien

Yesterday I have tested your new alpha, F-GGH-2P-1201161.GHX, on a slow and well sick -flu- run.

First I used my old 625M belt and my 580p ant+ belt.

I did not notice any HR peaks like I used to. I brought with me 580p (like I always do but today with a double chest strap set up) and my friend's 405.

Every time I checked 580 and 625xt, they were always in perfect sync (+/-1bpm).

Here's the graph (average HR for 580p = 161, for 625xt = 162). I don't know why but overlay graphs do not work for me in the latest TGP, so I am sharing graph separately. Also average distance in the lower right windows of TGP show no comma for 580p (25329km) but does for 625xt (25,55km). This seems to cause TGP to have some problems to display 580p activity/training graph properly in the overlay section.580p

625xt

As for the 405 I did not know you had to have the ant stick to upload data and I just have usb cable. Doh...And I did not set HR in my user field so I don't know how to check average HR in my historic, so I'll it go.BTW bezel does not work super dooper in cold weather.

------------------------Today I had fever so I decided to test new 625XT HR belt along ant+ belt on a small run around the corner (with the new alpha firmware).

I took a least one minute without moving before starting to run and did the same after the run.

So my conclusion is that I do suspect intermittent or bad contact/solderings into the new belt electrodes. Could someone check soldering if there is? I can check resistance next week if I have time but would like to see a schematic of how it's done inside.

My hypothesis goes in the same way than Ander's remark about moving or not for bpm precision: not moving = better contact, moving = increase bad contact.

PS Partyman and Longjog, I deleted my old thread Eureka: HR problem solved! including your posts to not induce people in error and make them think that the problem was solved. Hope it does not matter with you...

And my apologies for having confused anyone with my old and new belt mistake. They look so much the same when there is not much light ;-)

canadien

« Last Edit: February 02, 2012, 10:04:45 am by canadien »

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canadien

Old graph was the same of 625xt cause TPG was unable to refresh window adequately resulting into confounding the same graph as 625xt. Now you can see that two peaks differ from 580p graph, which is still much reasonable.

finally I was able to record some data for HRM values and I want to show the followingpictures, which show what I "felt" all the time:

Please first have a look at the following two screen shots:Both are taken simultaniously during the same run. I had the new GH-625XT on one arm,the old GH-625 on the other. And I used the old HRM belt (the one belonging to GH-625).The values are almost the same and it's hard to find a difference. Further more, the valuesare in a range what is my normal heart rate. So - that is fine and is exactly what I expected !

GH-625XT with old HRM belt.

GH-625 with old HRM belt.

Now have a look at the next pair of screen shots. This has been taken 3 days later at thesame track. Again with GH-625XT on one arm and GH-625 on the other. This time I usedthe new HRM belt (belonging to the new GH-625XT).There are some peaks (which hopefully are not created by my heart) and values differ fromone watch and the other:

GH-625XT with new HRM belt.

GH-625 with new HRM belt.

This is what I have seen already in some other test runs, but data was never comparable as it is now. My conclusion is, that the new HRM belt might cause some more peaks and so I will usethe old one from now on.

Regards, Hubert

Hi Hubert,

Perhaps to wear the new belt with logo up side down will to improve this problem.And we have the new firmware of GH-625XT (F-GGH-2P-1201201) to improve this.

in the meantime I could do three tests with FW F-GGH-2P-1201161.GHX.First test I used my Polar Wear-Link T31 coded belt. With the earlier firmware this worked fine in opposition to the original-GS-belt, but with F-GGH-2P-1201161.GHX the 625XT did always show heartrates around 68 bpm. In combination wit the Polar-Belt this FW-Version semms not compatible with my Polar-belt. (Polar S810i was fine).Next test I did a slow regeneraration-run with the original GS-belt HR around 138 bpm. Problem seems to be solved. Polar S810i watch and GH-625 XT did have very similar values. But at the end of my run, I did speed up a little HR around 155 bpm and at this time I could watch the heartrate shown by GH-625XT was "jumping" in a wider range again like I am used it from the times before.Finaly yesterday I did an other run in moderate tempo HR AVG 146 bpm but with pumpy trackparts HR max. 161 bpm, using GS-belt. This time the accuracy was like my Polar S810i all the time. Same AVG and MAX-value both watchesConclusion: It seems GS is on the right way to get the problem solved. But the upcoming inaccuracy at the end of the second run could be a sign the problem isn´t finaly solved.

Geoffrey, please mail the actual FW-Version for further tests and could you explain please, what you have changed?

Today bad success with FW 1201161. First 10 minutes seems to be okay but than to much jumping in a wide range while Polar S810i was well.The difference between the three times before was: I did wear a tight undershirt of function-fibre this time. Maybe error really caused by electrostatic problem which isn´t filtered by GH-625XT.

after installing gerhards Overlay-plugin for ST3 I could create this overlay with red graph from Polar, blue GH-625XT

@canadien: I If the belt would be shielded maybe it would be a problem to send a signal. Maybe it could be solved with a grounded board. But: If Polar can filter the signal. GS should be able to do also. Or it is a complete other algorythm for HR. Or it has to do with processor capacity used for HR-calculation. Questions nothing than questions.

Not much to compare with, but I have better results:I have only done two activities with the new FW. On trail run, one walk (as well as a few short tests). Both had very small HR difference and displayed a a much smaller dist addition than previously (compared to my other device). The walk had a indoor rest part where the 625XT was much better: The incorrect distance was lower than for the other device.However, for the trail run there is an incorrect 69,9s interval between the first and second point, so the total time is incorrect. (The test activities also have strange gaps, but there the GPS may have been lost, even if there were HR.)

After bad experiences with the new firmware-version (1201201) also, I tried the both watches with my Polar- belt Wearlink T31coded (with wearing a tight undershirt, I normaly have always big differences beteen the HRM-values!).

Here is the result:red: Polar S810i, blue GH-625XT

The graph downside ist the difference betwen two graphs above. The points where the difference is big, I did have a stop with my friends. The big diffferences are caused by interferences with the HRM-signals of my friends belts and different smoothing surely.

Well, the latest update seem about the same for HR. Some high effort stretches gives very high readings, the ANT device close to what I expect.

For distance though, the accuracy is maybe slightly improved. Large stretches it is the same as the ANT device I compare with, but there are some occasional "jumps". Some may be motivated, but I feel that overall reporting is closer to the "wheel" based distance.The device still reports 1-2% longer distances, post processing (I use 3 sec recording) 0.5-1%.

I like that the HR sensor is neat. However, if I hold the band in one hand and wave it, the watch shows a HR of about 80 bpm (it beeps too). There seem to be some mechanical problem with the band that can why the high values go down when stopping. I normally get high readings when running fast with high cadence. Today's trail run on icy trails also required tripping w high cadence, then there were several sections. As most users on the forum, this is an early produced unit, I guess longjogs is even earlier.